Ethanol and Hydrogen gas-sensing properties of CuO-CuFe2O4 nanostructured thin films

TL;DR

This study develops CuO-CuFe2O4 nanostructured thin films via sputtering and oxidation, demonstrating their effective sensing capabilities for ethanol and hydrogen gases at elevated temperatures, with notable response times and sensitivities.

Contribution

It introduces a novel fabrication method for porous CuO-CuFe2O4 thin films and evaluates their gas sensing performance for ethanol and hydrogen.

Findings

Highest hydrogen response of 79% at 400°C for 500 ppm

Response times of approximately 60s for hydrogen and 90s for ethanol

Sensor response increases with gas concentration from 10 to 500 ppm

Abstract

Nanocrystalline CuO-CuFe2O4 composite thin films were developed from CuFeO2 ceramic target using a radio frequency sputtering method followed by a thermal oxidation process. This fabrication process helps to develop porous sensing layers which are highly desirable for solid state resistive gas sensors. Their sensing properties towards ethanol and hydrogen gas in dry air were examined at the operating temperatures ranging from 250 deg C to 500 deg C. The electrical transients during adsorption and desorption of the test gases were fitted with the Langmuir single site gas adsorption model. A composite thin film with a total thickness of 25 nm showed highest response (79%) towards hydrogen (500 ppm) at the operating temperature of 400 deg C. The shortest response time (tres) was found to be ~60 and ~90 seconds for hydrogen and ethanol respectively. The dependence of the response of the sensor on gas concentration (10-500 ppm) was also studied.